CASE STUDY -- Methyl Bromide Alternative
Telone® C-17 and Tillam Use on Florida Fresh Market Tomatoes
Summary
In four recent studies, a combination of the pesticides Telone® C-17 and Tillam® has achieved yields similar to those obtained by fumigation with methyl bromide for Florida tomatoes intended for fresh markets. These chemicals were applied to control yield reducing diseases, nematodes, soil insects, and weeds in three trials conducted by University of Florida researchers and one conducted by DowElanco, the manufacturer of Telone®.
Telone® C-17, a DowElanco product registered for preplant fumigation, contains 78 percent 1,3-dichloropropene (1,3-D) and 17 percent chloropicrin. Telone® products, which contain the chemical 1,3-D, are recognized as effective preplant nematicides (Youngson, et al. 1981), and 1,3-D also suppresses some plant diseases (e.g., Fusarium wilt of cotton, Verticillium wilt of mint) (DowElanco 1994b). Chloropicrin, primarily a fungicide, is commonly used with methyl bromide in fumigation (DowElanco 1994b). Tillam®, a selective herbicide containing the active ingredient pebulate, is added for control of weeds (especially nutsedge) (Gilreath 1994a, Weed Control Manual 1994). Used together, these chemicals can achieve control of nematodes, weeds and a variety of diseases at levels comparable to those achieved with methyl bromide and chloropicrin (DowElanco 1994b, Gilreath 1994a).
Benefits of Telone C-17 and Tillam for Florida Fresh Market Tomatoes
- reduces incidence of diseases, especially
Fusarium wilt and crown rot.
- suppresses weeds including purple
nutsedge.
- achieves similar nematode control as
methyl bromide.
Florida Fresh Market Tomatoes
Florida is the largest fresh market tomato producer in the United States. In 1993, Florida growers produced nearly 425 million pounds of tomatoes valued at close to $600 million. The industry consists of approximately 300 growers affiliated with 75 grower cooperatives and packing houses located throughout Florida. Most large commercial growers cultivate tomatoes in each of Florida's 5 major production areas located in the mid to southwestern portions of Florida. The growing season begins in the northern production areas in the fall and moves south as winter approaches where the bulk of production occurs. As spring approaches, the focus shifts back to the mid portions of the state (ICF 1994).
Overview of Methyl Bromide Usage
The combination of methyl bromide and chloropicrin has been used extensively in Florida to suppress tomato crop pests such as nematodes, diseases/fungi and weeds (Dickson 1994a). In 1992 and 1993 approximately 3,500 to 4,000 metric tons of methyl bromide were used on the Florida tomato crop, approximately 14 percent of total annual methyl bromide consumption in the United States (FASS 1994, SRI 1993, UNEP 1995).
Testing of Alternatives
Several studies have been conducted comparing control of soil borne pests obtained with methyl bromide fumigation to that obtained by Telone® C-17 and Tillam® applications. One study conducted by the University of Florida demonstrated that 1,3-D plus chloropicrin and Tillam® reduced the incidence of Fusarium wilt, achieved similar results as methyl bromide on purple nutsedge, and in the fall, resulted in better control of crown rot than methyl bromide treatments (Gilreath 1994b). Other chemicals tested included Basamid® and metam sodium. Other studies conducted by University researchers revealed similar results. Generally, the combination of Telone® C-17 and Tillam® achieved higher yields than any of these products used alone or in other formulations and/or combinations. The following points highlight the important results of these research findings:
- A study compared methyl bromide treatments to five other fumigants including Telone® C-17 and Tillam® for control of root-knot nematodes (Meloidogyne arenaria race 1) and soil borne diseases (caused by Rhizoctonia solani, Fusarium spp. and Macrophomina phaseolina) on tomatoes in polyethylene mulch culture. Tomatoes were harvested at breaker stage and graded into marketable size categories (extra-large, large and medium). Relative marketable tomato yields of 77 percent were obtained from the plot treated with 1,3-D and pebulate as compared with 100 percent yields obtained with methyl bromide treatments (Dickson 1994b).
- In a study where nutsedge and root-knot nematodes were the major pests, tomatoes were harvested at breaker stage and graded into market size categories for comparison purposes. The use of Telone® C-17 and Tillam® resulted in yields 16-26 percent higher than those obtained with applications of chloropicrin, 1,3-dichloropropene plus C-17 without Tillam®, dazomet or metam sodium (drip applied). The yields recorded by Telone® C-17 and Tillam® were approximately 46 percent higher than those obtained with no treatment. Use of Telone® C-17 and Tillam® achieved 86 percent of the marketable yield relative to that obtained with methyl bromide and chloropicrin preplant fumigation (Locascio 1994).
Noting that pest populations can influence results, DowElanco reports that trials using Telone® C-17 in conjunction with Tillam® provide equal to slightly less than equal control of diseases and achieve equal control of nematodes, as well as nutsedge and other weeds as compared to methyl bromide. The yield and vigor of the tomatoes tested appeared similar to those grown using methyl bromide (DowElanco 1994b). The yield of market size tomatoes grown in soils treated with Telone® C-17 may increase with a later harvest date which allows for continued growth and development of the plants. Increasing the amount of chloropicrin applied from 17 percent to 25-35 percent is also being investigated and is expected to increase the product's effectiveness for controlling soil pathogens (Melichar 1995).
Availability and Regulatory Issues
Telone® products are currently available on a limited basis in Florida. The limited availability of Telone® in southern Florida is due to company decisions. Although regulatory issues have been a limiting factor in California (Melichar 1995), Telone® II is currently available in several counties after the California Department of Pesticide Regulation reinstated permits for Telone® II in California (DowElanco 1994a).
Costs of Alternative
The combination of Telone® C-17 and Tillam® is applied in a manner similar to the application of methyl bromide/chloropicrin; therefore a cost analysis is based on many of the same variables including: raw material costs, labor costs, machinery costs and the costs of time delays associated with protecting against phytotoxicity and addressing human health concerns. According to industry specialists, information on increased labor, machinery, and delay costs are still being investigated and could be a factor in limiting a broad shift from methyl bromide to this alternative (Botts 1995). An analysis of the raw material costs associated with fumigation for tomatoes in Florida is presneted below.
Comparison of Estimated Raw Materials Costs for Row Applications
Telone C-17/Tillam
Application Rate:
Telone C-17 - 17.5 gal/acre
Tillam 6 EC - 2 lb a.i./acre
Cost per Unit:
Telone C-17 - $15.25/gal
Tillam - $39.44/gal
Total Material Cost: $280/acre
Methyl bromide/chloropicrin (98:2)
Application Rates: 200 lb a.i./acre
Cost per Unit: $1.12/lb
Total Material Cost:$224/acre
Sources: Gilreath 1994a, Helena Chemical 1995, Asgrow 1995, and Lykes Agrisales 1995.
References
Asgrow. 1995 (February 1). Personal communication. Asgrow. Price Quote for Telone C-17, Methyl Bromide, and Tillam.
Botts. 1995 (January 30). Personal communication. Dan Botts, Florida Fruit and Vegetable Growers Association.
Dickson. 1994a (October 7). Personal communication. Don Dickson, Department of Entomology and Nematology, University of Florida. Gainesville, Florida.
Dickson. 1994b (November 13-16). "Evaluation of multi-purpose soil fumigants for root-knot nematode and soilborne disease management on tomato in Florida." D. Dickson, S. Locascio and T. Kucharek (Departments of Entomology and Nematology, Horticultural Sciences and Plant Pathology, University of Florida). 1994 International Conference on Methyl Bromide Alternatives and Emissions Reductions. Kissimmee, FL.
DowElanco. 1994a (December 7). Western Union Mailgram regarding California Department of Pesticide Regulation reinstatement of use permits for Telone II soil fumigant in selected California counties. Greg Warren and Ken Phelps. Indianapolis, Indiana.
DowElanco. 1994b (November 13-16). "Telone® soil fumigants as a methyl bromide alternative. Michael Melichar, Product Development Manager." 1994 International Conference on Methyl Bromide Alternatives and Emissions Reductions. Kissimmee, FL.
FASS 1994 (August 5). Agricultural Chemical Usage: Vegetables. Florida Agricultural Statistics Service. Orlando, Florida.
Gilreath. 1994a. "Development of Alternatives to Methyl Bromide in Tomato Production." J.P. Gilreath, J.P. Jones, and J. Overman, Gulf Coast Research and Education Center. In Report of Tomato Research: Supported by the Florida Tomato Committee 1993-1994. Institute of Food and Agricultural Sciences, University of Florida. Florida.
Gilreath. 1994b (November 13-16). "Soil-borne pest control in mulched tomato with alternatives to methyl bromide." J. Gilreath, J.P. Jones, A. Overman. Gulf Coast Research and Education Center. University of Florida. 1994 International Conference on Methyl Bromide Alternatives and Emissions Reductions. Kissimmee, FL.
Helena Chemical. 1995 (February 1, 1995). Personal Communication. Helena Chemical. Price Quote for Telone C-17, Methyl Bromide, and Tillam.
ICF. 1994 (November 7). Preliminary Case Study Examining Replacement of Methyl Bromide Use in Florida Fresh Market Tomato Production. ICF Incorporated. Washington, D.C.
Locascio. 1994 (November 13-16). "Nutsedge, root-knot nematode, and fungal control with fumigant alternatives to methyl bromide in polyethylene mulched tomato." S.J. Locascio, D. Dickson, T. Kucharek (Horticultural Sciences, Entomology and Nematology, and Plant Pathology Departments, University of Florida). 1994 International Conference on Methyl Bromide Alternatives and Emissions Reductions. Kissimmee, FL.
Lykes Agrisales. 1995 (February 1). Personal Communication. Lykes Agrisales. Price Quote for Telone C-17, Methyl Bromide, and Tillam.
Melichar. 1995 (January 30). Personal Communication. Mike Melichar. Product Development Manager. DowElanco. Indianapolis, Indiana.
SRI. 1993. Florida Vegetable Crop Markets, Nematicide and Soil Fumigant Use by Product for Tomatoes in 1993. SRI International.
UNEP. 1995. Montreal Protocol on Substances that Deplete the Ozone Layer. 1994 Report of the Methyl Bromide Technical Options Committee: 1995 Assessment. November 30, 1994. J. Banks (chair). UNEP Nairobi, Ozone Secretariat. Kenya.
Weed Control Manual. 1994. 1994 Weed Control Manual. Sine, C. and R. Meister (eds.), Meister Publishing Company. Willoughby, Ohio.
Youngson, et al. 1981 (September). Control of plant parasitic nematodes on established tree and vine crops with Telone II soil fumigant. Youngson, C., Turner, G. and F. O'Melia, Dow Chemical. Down to Earth. Volume 37, Number 3. The Dow Chemical Company. Midland, Michigan.
Please note that this publication discusses specific proprietary products and pest control methods. Some of these alternatives are now commercially available, while others are in an advanced stage of development. In all cases, the information presented does not constitute a recommendation or an endorsement of these products or methods by the Environmental Protection Agency (EPA) or other involved parties. Neither should the absence of an item or pest control method necessarily be interpreted as EPA disapproval.
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